Abstract

Recent retrievals of zonal thermal winds obtained in a cyclostrophic regime on Venus are generally consistent with cloud tracking measurements at mid-latitudes, but become unphysical in polar regions where the values obtained above the clouds are often less than or close to zero. Using a global atmospheric model, we show that the main source of errors that appear in the polar regions when retrieving the zonal thermal winds is most likely due to uncertainties in the zonal wind intensity in the choice of the lower boundary condition.

Here we suggest a new and robust method to better estimate the lower boundary condition for high latitudes, thereby improving the retrieved zonal thermal winds throughout the high latitudes middle atmosphere. This new method is applied to temperature fields derived from Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) data on board the Venus Express spacecraft. We obtain a zonal thermal wind field that is in better agreement with other, more direct methods based on either retrieving the zonal winds from cloud tracking or from direct measurements of the meridional slope of pressure surfaces.

Item Type:

Journal Article

Copyright Holders:

2011 Elsevier Inc.

ISSN:

0019-1035

Project Funding Details:

Funded Project Name

Project ID

Funding Body

Not Set

Not Set

FCT – Fundação para a Ciência e a Tecnologia (Portugal)

Extra Information:

This aritcle has been available online since 30 July 2011, but is still waiting for a special issue to be printed. Am enetring now as 'in press' on request for the RPS/REF

NOTICE: this is the author’s version of a work that was accepted for publication in Icarus. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Icarus, 217(2) Feb 2012 10.1016/j.icarus.2011.07.010